The present invention relates to a pulsoximetry ear sensor structure for measuring the oxygen saturation in the blood of a patient.
In a known, standard non-invasive method of blood pulsoximetry, light with at least two wavelengths is beamed into the tissue of a patient. Conclusions are drawn concerning the oxygen saturation from the attenuation of the alternating component of the reflected or transmitted signal. Typically light-emitting diodes and photocells are mounted on a sensor structure for this purpose. The ear lobe is a body part which is particularly suitable for the measurement. Photovoltaic cells can be applied closely and without any tilting to the ear lobe skin, so that the signal alternating component, which is smaller by an order of magnitude than the signal constant component, can be determined in an optimum manner.
In the hitherto known ear sensor structures the sensor elements are fixed to a support, which in much the same way as two legs of a clothes, pin are interconnected by a spring clip. The spring clip applies a spring tension to the legs as is necessary for fixing the sensor structure to the ear lobe. The spring clip must be separately fitted for this purpose. U.S. Pat. No. 4,685,464 discloses a similar sensor structure for measurements on a figure. Such sensor structures, which require an additional spring, are difficult to clean, because the clip causes the sensor structure to have numerous dirty edges which are difficult to access. In addition, a separate fitting of the spring clip is necessary.
An object of the present invention is to provide a new and improved pulsoximetry ear sensor structure.